Frank Herbert's Dune must be the king of fantasy SF, if there is such a thing. It doesn't really have aliens, but it feels like sf and fantasy.
Ursula K Le Guin's The Left Hand of Darkness has a fully realised alien world, Winter. It's the efforts a lone envoy to admit this planet to an the enlightened harmony of worlds.
My favourite SF book is Starmaker by Olaf Stapledon. It begins in England in the 30s but expands out to encompass stranger and stranger alien races and the history of all cosmoses.
Ray Bradbury's The Martian Chronicles is a great book.
Ursula K Le Guin's The Left Hand of Darkness has a fully realised alien world, Winter. It's the efforts a lone envoy to admit this planet to an the enlightened harmony of worlds.
My favourite SF book is Starmaker by Olaf Stapledon. It begins in England in the 30s but expands out to encompass stranger and stranger alien races and the history of all cosmoses.
Ray Bradbury's The Martian Chronicles is a great book.